The goal of this research project is to develop sensitive immunoassays to measure antibody (Ab) against well-defined antigens of Candida albicans and to detect such antigens in sera of infected patients at concentrations less than 40 ng/ml. An enzyme-linked immunosorbent assay (ELISA) has been devised to quantitate serum levels of Ab against Candida cell wall mannan. This ELISA is being used to measure anti-cell wall mannan Ab levels in sequential sera from patients who are at risk for developing severe Candida infections. An ELISA will be developed which can detect cell wall mannan in sera from infected patients. A major cytoplasmic antigen (mAg) of Candida has been discovered and partially characterized. Purified preparations of mAg have been obtained from cytoplasmic extracts of Candida using DEAE-cellulose and concanavalin A-sepharose chromatography. Antisera against purified mAg will be produced in rabbits and used to construct double-antibody sandwich ELISA's that can quantitate anti-mAg Ab levels and detect mAg in human sera. The usefulness of these ELISA's in the diagnosis of deep-seated Candida infections in humans will then be studied.